Traditional recreational scanning sonar systems are often incapable of generating real-time sonar imagery. For example, sidescan sonar systems generate useful imagery only when attached to a moving boat. This can be problematic for fishermen, whose vessels may remain stationary for extended periods of time while fishing. And, although some sonar systems are capable of generating real-time sonar imagery, these systems are incapable of generating the historical sequence of images to which many fisherman are accustomed.